The invention relates to a T-shaped three-dimensional guard folding device on the production line of disposable sanitary accessories. The problem that the prior device only can fold out a single-shaped three-dimensional guard with an unreliable elasticity function and a leakage proof function is solved. The structural improvement is characterized in that the device comprises three forming foldingmechanisms, wherein, two folding stands of a first forming folding mechanism are arranged on a folding seat in parallel, an interval between the two folding stands is zero, the longitudinal input ends of the two folding stands are respectively connected with two guide plates which compose a dovetail shape and incline downwards, folding legs turned outwards are arranged on the transversal outer side edge of the two folding stands respectively; the interval between the folding stands of a second farming folding mechanism and a third farming folding mechanism is 70-120 mm, the structure of the T-shaped three-dimensional guard folding device of the invention is simple and compact, and the adjustment and the maintenance are flexible and convenient. The invention is suitable for the leakage proof T-shaped elastic three-dimensional guard folding production of products such as adult urine trousers and diaper, baby urine trousers and diaper and sanitary towel.